The present application relates to storage systems, and more specifically, to storage systems that include multiple storage disks.
Storage systems include multiple disks arranged in an array, such as using Redundant Array of Independent Disks (RAID) techniques. Typically, such arrangements are effective for Hard-Disk Drive (HDD) data protection because the probability of encountering a secondary fault during repair of a first failed device is extremely low. Even though at first glance one might assume that a Solid State Drive (SSD) will have similar failure characteristics as of an HDD, that is not the case. Attempting to apply RAID techniques to SSDs can prove ineffective since SSD failure more often occurs from wearout and not due to normal random failure mechanisms.
Further, SSD wearout failures typically occur in a very small time window, which may cause all the SSD devices in the RAID array to fail at about the same time.